At the office building, Storey C and Storey D had an equal number of chairs at first. If 9 chairs were removed from Storey D and 4 times as many chairs were removed from Storey C as Storey D, the number of chairs in Storey D would be 4 times as many as in Storey C. Find the number of chairs on each storey.
|
Storey C |
Storey D |
Before |
1 u |
1 u |
Change |
- 36 |
- 9 |
After |
1 u - 36 |
1 u - 9 |
Number of chairs removed from Storey C
= 4 x 9
= 36
Number of chairs on Storey C and Storey D at first is the same.
Number of chairs on Storey D is 4 times as many as Storey C in the end. If the number of chairs on Storey C increases by 4 times, the number of chairs on Storey C and Storey D will be the same.
4(1 u - 36) = 1 u - 9
4 u - 144 = 1 u - 9
4 u - 1 u = 144 - 9
3 u = 135
1 u = 135 ÷ 3 = 45
Number of chairs in each floor
= 1 u
= 45
Answer(s): 45